Formula
Average depth = (shallow depth + deep depth) ÷ 2. Measured volume m³ = length × width × average depth × shape factor. Litres = m³ × 1,000. US gallons = litres ÷ 3.785411784. Planning volume = measured volume × (1 + allowance percent ÷ 100).
Home & Construction
Pool Volume Calculator
Estimate swimming pool volume from length, width, average depth and shape, with litres and US gallons shown for treatment, heating and maintenance notes.
Home & Construction
Pool Volume Calculator
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Live resultReadyCalculator queued
Formula used
Average depth = (shallow depth + deep depth) ÷ 2. Measured volume m³ = length × width × average depth × shape factor. Litres = m³ × 1,000. US gallons = litres ÷ 3.785411784. Planning volume = measured volume × (1 + allowance percent ÷ 100).
This is the method behind the answer, so the result can be checked rather than simply trusted.Visual grid
This result measures part of the space you live in
Length, area, volume and material estimates are grid problems too: measure the space, account for edges and allowances, then turn the pattern into a number you can use.
Micro-timehours, minutes, shiftsHuman scaledays, weeks, projectsMacro-timemonths, years, calendars
Measured outputReady
Space calculations turn a real surface, room, run or volume into cells, edges and allowances that can be quoted, ordered or checked.
CalculationTime
Pool Volume Calculation Report
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Inputs
- Pool length
- 8 metres
- Pool width
- 4 metres
- Shallow-end depth
- 1.1 metres
- Deep-end depth
- 1.8 metres
- Shape factor
- 1
- Safety allowance
- 0 percent
Method
Average depth = (shallow depth + deep depth) ÷ 2. Measured volume m³ = length × width × average depth × shape factor. Litres = m³ × 1,000. US gallons = litres ÷ 3.785411784. Planning volume = measured volume × (1 + allowance percent ÷ 100).
- For an 8 m by 4 m pool with 1.1 m shallow depth, 1.8 m deep depth and rectangular shape factor 1.00: average depth is 1.45 m. Volume = 8 × 4 × 1.45 × 1.00 = 46.4 m³, which is 46,400 litres or about 12,257.6 US gallons.
Assumptions
- Length, width and depths are internal water measurements in metres.
- Shape factor is a planning approximation: 1.00 rectangular, about 0.85 for many rounded/kidney pools and about 0.79 for oval or round pools.
- The result is a volume estimate for planning. Chemical dosing, safety rules, water testing and equipment sizing should follow product labels and qualified pool guidance.
- US liquid gallons are shown for comparison; imperial gallons are different and are not used here.
Notes
Use this space on the printed report for client, supplier, classroom, job-location, measurement, quote or approval notes.
Worked example
For an 8 m by 4 m pool with 1.1 m shallow depth, 1.8 m deep depth and rectangular shape factor 1.00: average depth is 1.45 m. Volume = 8 × 4 × 1.45 × 1.00 = 46.4 m³, which is 46,400 litres or about 12,257.6 US gallons.
Professional note
Master’s Tip: write down whether the depth was measured at the waterline, the tile line or the shell floor. A small depth assumption changes the litres enough to affect chemical and heating estimates.
Regional and unit assumptions
Standard or basis: metric volume arithmetic using 1 cubic metre = 1,000 litres and 1 US liquid gallon = 3.785411784 litres. No chemical-dose, health-code, engineering, safety-barrier or equipment-sizing standard is claimed.
Assumptions and limitations
- Length, width and depths are internal water measurements in metres.
- Shape factor is a planning approximation: 1.00 rectangular, about 0.85 for many rounded/kidney pools and about 0.79 for oval or round pools.
- The result is a volume estimate for planning. Chemical dosing, safety rules, water testing and equipment sizing should follow product labels and qualified pool guidance.
- US liquid gallons are shown for comparison; imperial gallons are different and are not used here.
Methodology & Accuracy
How this calculator is checked
CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.
Formula used
Average depth = (shallow depth + deep depth) ÷ 2. Measured volume m³ = length × width × average depth × shape factor. Litres = m³ × 1,000. US gallons = litres ÷ 3.785411784. Planning volume = measured volume × (1 + allowance percent ÷ 100).
Standard or basis
Standard or basis: metric volume arithmetic using 1 cubic metre = 1,000 litres and 1 US liquid gallon = 3.785411784 litres. No chemical-dose, health-code, engineering, safety-barrier or equipment-sizing standard is claimed.
Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.Master's Tip
Master’s Tip: write down whether the depth was measured at the waterline, the tile line or the shell floor. A small depth assumption changes the litres enough to affect chemical and heating estimates.
Related calculators
Questions
How do you calculate pool volume?
Multiply internal length by width by average water depth, then adjust for shape. Convert cubic metres to litres by multiplying by 1,000.
How do I handle a pool with a shallow and deep end?
Use average depth: add the shallow-end depth and deep-end depth, then divide by two. That works for a simple sloping floor estimate.
What shape factor should I use?
Use 1.00 for a rectangle, about 0.85 for many rounded or kidney-style pools, and about 0.79 for oval or round pools. Irregular pools should be measured in sections when accuracy matters.
Can I use this for pool chemical dosing?
Use it as a volume record, then follow the chemical product label, water-test result and local pool professional guidance. Do not treat this page as a chemical-safety instruction.
Does this use US or imperial gallons?
The gallon result uses US liquid gallons. Imperial gallons are larger, so do not mix the two bases in a maintenance record.
Calculation note
Pool-volume arithmetic is practical geometry. A swimming pool is not just a rectangle on paper: sloped floors, rounded ends, steps, benches and uncertain waterline measurements can all change the usable water volume.
Average depth makes a sloped floor calculable
Many pools are shallower at one end and deeper at the other. Averaging those two water depths gives a practical first estimate for a simple, evenly sloped floor.
Shape factor keeps rounded pools honest
A rectangular pool fills the whole length-by-width box, but oval and kidney shapes do not. The shape factor reduces the rectangle volume so the estimate better matches the actual water shape.
Volume records support maintenance decisions
Pool water volume is commonly needed before chemical treatment, heating estimates, refill planning or equipment discussions. A printable record is useful because it preserves the measurements, formula, date, page context and notes area.
Sources and further readingNIST: SI units and metric relationshipsNIST Handbook 44 Appendix C: General Tables of Units of Measurement